Question

Which of the following compounds is/are polar covalent: `H_2O`, `CaCl_2`, `N_2`, `CH_4`, `HNO_3`? How is this determined?

Answer 1

Molecular polarity is the result of the vector sum of the individual bond dipoles..........

Explanation:

And with ionic species, because the charges are formally SEPARATED, we generally do not speak of polarity. So for `CaCl_2` we speak of an ionic salt.

On the other hand, for `""^(delta+)H-stackrel(delta-)O-H`, `""^(delta+)H-stackrel(delta-)Ostackrel(+)N(=O)(-O^(-))` (the nitrogen is also formally quaternized), there is charge separation, polarity, and thus these are polar covalent molecules.

On the other, other hand, for `N_2`, and `CH_4`, there is NO polarity, no charge separation, and these species are classic non-polar molecules.